Siganid

Rabbitfishes or spinefoots are perciform fishes in the family Siganidae. The 29 species are in a single genus, ''Siganus''. In some now obsolete classifications, the species having prominent face stripes—colloquially called foxfaces–are in the genus ''Lo''. Other species, such as the masked spinefoot (''S. puellus''), show a reduced form of the stripe pattern. Rabbitfishes are native to shallow waters in the Indo-Pacific, but '' S. luridus'' and '' S. rivulatus'' have become established in the eastern Mediterranean via Lessepsian migration. They are commercially important food fish, and can be used in the preparation of dishes such as ''bagoong''.

Taxonomy

The Siganidae was first formally described as a family in 1837 by the Scottish naval surgeon, naturalist and arctic explorer Sir John Richardson. The genus ''Siganus'' was described in 1775 by the Danish zoologist Johan Christian Fabricius with ''Siganus rivulatus'', a species also described by Fabricius in 1775, designated as he type species. The description was based on notes taken by the naturalist Peter Forsskål when he was on the Danish Arabia expedition (1761–67) and was published in Carsten Niebuhr's ''Descriptiones animalium avium, amphibiorum, piscium, insectorum, vermium; quae in itinere orientali observavit Petrus Forskål. Post mortem auctoris edidit Carsten Niebuhr''. Catalog of Fishes lists the authority as " Fabricius . C.(ex Forsskål) in Niebuhr 1775" and states that the genus is valid as "''Siganus'' Fabricius 1775".

Carl Linnaeus originally described the genus ''Teuthis'', with the type species being ''Teuthis hepatus''. One of the type specimens he used looks like ''Siganus javus'', although the other is definitely not a rabbitfish, and the International Commission on Zoological Nomenclature has been asked to suppress the name ''Teuthis'' in favour of ''Siganus'' to reflect the prevailing usage.

The family Siganidae is classified as one of two families in the superfamily Siganoidea, within the suborder Percoidei of the order Perciformes in the 5th edition of ''Fishes of the World''. In other classifications it is classified as a family within the order Acunthuriformes, or as one of a group of families classified as '' incertae sedis'' within the series Eupercaria. The name ''Siganus'' is a latinisation of the local Arabic name for the marbled rabbitfish (''S. rivulatus'') in Yemen, ''Sidjan'' which can also be written as ''Sigian'', and means "rabbitfish".

In 2007 Kurriwa ''et al.'', outlined a way to split the genus—if the scientific community so desires:
* An ancient group containing e.g. ''S. woodlandi''
* Another fairly small group containing, e.g., the '' S. canaliculatus''/'' S. fuscescens'') complex
* The remainder of'' Siganus'', including the foxfaces

Other lineages might exist and make obsolete the somewhat weak distinction between the second and third groups. Also, it is not known where the type species '' S. rivulatus'' would fall, hence names for these three subgenera or genera are not established at present.

Hybridizaton has played a role in the evolution of the Siganidae, as evidenced by comparison of mtDNA cytochrome ''b'' and nDNA internal transcribed spacer 1 sequence data. Evidence exists of interbreeding between '' S. guttatus'' and '' S. lineatus'', as well as between '' S. doliatus'' and '' S. virgatus''.

Also, either females of the last common ancestor of '' S. puellus'' and the '' S. punctatus'' interbred with females ancestral to the main non-foxface lineage, or males of the former hybridized with females of the last common ancestor of '' S. punctatissimus'' and the foxfaces, while males of the latter mated with females of the original foxface species.

An individual was found that looked like a slightly aberrant blue-spotted spinefoot ('' S. corallinus''). On investigation, it turned out to be an offspring of a hybrid between a female of that species and a male masked spinefoot, which had successfully backcrossed with the blue-spotted spinefoot.

Species

As noted above, several presumed species are suspected to actively interbreed even today; these might warrant merging as a single species. This applies to the white-spotted spinefoot ('' S. canaliculatus'') and the mottled spinefoot ('' S. fuscescens''), and to the blotched foxface (''S. unimaculatus'') and the foxface rabbitfish (''S. vulpinus''). Alternatively they might be very recently evolved species that have not yet undergone complete lineage sorting, but their biogeography suggests that each group is just color morphs of a single species. On the other hand, the morphologically diverse blue-spotted spinefoot (''S. corallinus'') might represent more than one species; orange individuals are found at the north of its range, while yellow ones occur to the south, and these two may be completely parapatric.

There are currently 29 recognized species in this genus:
* '' Siganus argenteus'' ( Quoy & Gaimard, 1825) (Streamlined spinefoot)
* ''Siganus canaliculatus'' ( M. Park, 1797) (White-spotted spinefoot)
* '' Siganus corallinus'' ( Valenciennes, 1835) (Blue-spotted spinefoot)
* ''Siganus doliatus'' Guérin-Méneville, 1829 (Barred spinefoot)
* ''Siganus fuscescens'' ( Houttuyn, 1782) (Mottled spinefoot)
* ''Siganus guttatus'' (Bloch, 1787) (Goldlined spinefoot)
* '' Siganus insomnis'' Woodland & R. C. Anderson, 2014 (Bronze-lined rabbitfish)
* ''Siganus javus'' ( Linnaeus, 1766) (Streaked spinefoot)
* '' Siganus labyrinthodes'' (Bleeker

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